1. Field of the Invention
The present invention is directed generally to a wireless communication network and, more particularly, to a system and method for providing Voice over Internet Protocol (VoIP) quality of service (QoS) support in a wireless communication network.
2. Description of the Related Art
The use of Voice over Internet Protocol (VoIP) is common and its use is increasing. Standards exist for the use of VoIP in wired networks. The present IEEE 802.16e standards do not have native VoIP support in the Media Access Control (MAC) layer. It does define the mechanisms for Service Flows to provide Quality of Service (QoS) to traffic, but leaves the implementation of decision of traffic selection, marking, and classification up to the vendor. To support QoS for Mobile VoIP or Fixed VoIP, service providers are depending on Mobile Subscriber Station (MSS) vendor implementation in 802.16e.
The 802.16e standards were designed to support multiple QoS classes by having 5 different Service Flow types. Unsolicited Grant Service (UGS) and Extended Real Time Polling Services (ertPS) were created to support VoIP with fixed grant sizes at regular intervals. Best Effort (BE) was designed to carry delay and jitter tolerant data traffic.
The mechanisms to use these Service Flows for various traffic types were left up to vendor implementation. In the Downlink, with traffic flow from the base station to an Access Service Network (ASN) Gateway (GW), the vendor is supposed to map Layer 3 Differentiated Services Code Point (DSCP) markings or Layer 2 User Priority (UP) markings to the right service flow.
This put the onus of classification and marking (L3 DSCP or L2 UP field) of packets on an Application aware device external to the Base Station/ASN GW. This can be achieved by service providers by using an IP multimedia subsystem (IMS) or other Deep Packet Inspection boxes to map Application layer traffic into various Layer 3 or Layer 2 traffic types.
In the Uplink, however, while supporting IP convergence sub-layer (IPCS), the Mobile Station vendor has the onus of doing the Layer 3 DSCP packet marking so that the packets can be sent on the intended WiMAX Service Flow (UGS/ertPS vs. BE). This is a bigger challenge than the downlink direction because of the nature of the devices (e.g., a mobile PC card, residential consumer premise equipment (CPE) or handset) and no standard definition of packet classification.
Therefore, it can be appreciated that there is a need for VoIP QoS support in an uplink and downlink in a wireless communication network. The present invention provides this and other advantages as will be apparent from the following detailed description and accompanying figures.